[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: $C030 -- Tape Toggle Question
- Subject: Re: $C030 -- Tape Toggle Question
- From: "Michael J. Mahon" <mjmahon@aol.com>
- Date: Thu, 17 Mar 2005 23:25:41 -0800
- In-reply-to: <cJ6_d.12811$WK2.284@newssvr30.news.prodigy.com>
- Newsgroups: comp.sys.apple2
- References: <iILZd.19793$YD4.16460@newssvr12.news.prodigy.com> <qhfyyv3vsr.fsf@ruckus.brouhaha.com> <cJ6_d.12811$WK2.284@newssvr30.news.prodigy.com>
- User-agent: Mozilla Thunderbird 1.0 (Windows/20041206)
- Xref: g2news1.google.com comp.sys.apple2:9534
Bryan Parkoff wrote:
Eric,
Then, I don't understand what strobe is for to do with I/O. If you use
STA $2000, speaker will be turned on constantly without turning it off until
second STA $2000 has to be executed by turning it off, otherwise STA $2000,X
allows to turn on and off speaker during two cycles.
Yes, but the question is: what is the application for a one-microsecond
pulse on the speaker? Or two consecutive one-microsecond pulses?
Although one might be able to come up with uses for short pulse
streams, they would generally be more useful if coming from the
STROBE output on the game port. In practice, most strobe uses
require single pulses (for handshaking), not multiple ones.
The fact that the 6502 can produce multiple pulses with a single
instruction is a kind of curiosity with few practical uses.
Generally, you want to toggle the speaker, leave it there for a while,
then toggle it back. If you repeat this at an audio rate, an audible
tone is produced.
If you toggle the speaker at an ultrasonic rate, with varying duty
cycle, then "arbitrary" waveforms can be produced from the speaker.
(See my web site for SOUND.EDITOR and DAC522.)
-michael
New Applesoft BASIC interface for NadaNet networking!
Home page: http://members.aol.com/MJMahon/